A class-D amplifier or switching amplifier is an electronic amplifier which, in contrast to an active resistance used in linear mode AB-class amplifiers, uses the switching mode of transistors to regulate power delivery. The amplifier, therefore, features high power efficiency (low energy losses), which additionally results in lower weight by eliminating the bulky heat sinks. Additionally, if voltage conversion is necessary, a higher switching frequency allows bulky audio transformers to be replaced by small inductors. Low pass LC-filtering smoothes the pulses out and restores the signal shape on the load.